Heretofore, many efforts have been made to provide an apparatus for use by a player to improve his coordination and timing as well as for use as an exercise device for improving muscle tone and the like. Generally, these prior efforts have been limited to particular sports, such as tennis, golf, tether ball and the like, since each sport requires different physical abilities and different muscular coordination to improve a player's timing and different phases of each sport require different coordination and timing. For example, in the game of tennis, the serve is entirely different from ground strokess, and even ground strokes differ as noted by the different strokes required for driving overspin shots as compared with lob shots.
Many prior art apparatus for practicing tennis include an elongate, pivoted arm with a ball mounted at one end and a resilient member attached to the arm intermediate the ball and the pivot so that when the ball is struck by a racket, the arm pivots about its axis of rotation until it engages a rebound surface after which the resilient member returns the arm to a stop which holds the arm in an upright position. One of the disadvantages of such apparatus is that the ball is usually in a fixed position when struck. U.S. Pat. Nos. 2,578,313 to Moseley, 2,713,487 to Jaedikes and 3,924,853 to Schleeger are exemplary of such apparatus.
In some prior art apparatus, the ball is freely supported on one end of a pivoted arm having a resilient member attached thereto when the arm is held in a cocked position. When the arm is released, the resilient member pivots the arm to a vertical position against a stop and the ball is propelled in free flight toward a player. This type of apparatus has the disadvantages of requiring a large space for use, retrieval of the ball and recocking of the apparatus after each use. An example of this type of apparatus is shown in U.S. Pat. No. 2,080,958 to Beasley et al.
In other prior art apparatus, a pivotally mounted arm has been provided with a ball attached to one end and one or more resilient members attached to the arm to cause the arm to oscillate when the ball is struck by a racket or the like. In some cases, such as U.S. Pat. No. 3,876,203 to Gold, a plurality of springs are attached to the arm to produce a disadvantageous erratic movement of the ball. In other cases, such as British Pat. No. 370,590 to Stygall, the axis of rotation of the arm is located intermediate its ends, and the resilient member is attached to the end of the arm remote from the ball. This type of device imparts a substantial stretch or elongation to the resilient member and has the disadvantage of producing an unnatural feel when the ball is struck.